arch/openrisc/kernel/head.S

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * OpenRISC head.S
   4  *
   5  * Linux architectural port borrowing liberally from similar works of
   6  * others.  All original copyrights apply as per the original source
   7  * declaration.
   8  *
   9  * Modifications for the OpenRISC architecture:
  10  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  11  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12  */
  13
  14 #include <linux/linkage.h>
  15 #include <linux/threads.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/serial_reg.h>
  19 #include <linux/pgtable.h>
  20 #include <asm/processor.h>
  21 #include <asm/page.h>
  22 #include <asm/mmu.h>
  23 #include <asm/thread_info.h>
  24 #include <asm/cache.h>
  25 #include <asm/spr_defs.h>
  26 #include <asm/asm-offsets.h>
  27 #include <linux/of_fdt.h>
  28
  29 #define tophys(rd,rs)                           \
  30         l.movhi rd,hi(-KERNELBASE)              ;\
  31         l.add   rd,rd,rs
  32
  33 #define CLEAR_GPR(gpr)                          \
  34         l.movhi gpr,0x0
  35
  36 #define LOAD_SYMBOL_2_GPR(gpr,symbol)           \
  37         l.movhi gpr,hi(symbol)                  ;\
  38         l.ori   gpr,gpr,lo(symbol)
  39
  40
  41 #define UART_BASE_ADD      0x90000000
  42
  43 #define EXCEPTION_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_SM)
  44 #define SYSCALL_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_IEE | SPR_SR_TEE | SPR_SR_SM)
  45
  46 /* ============================================[ tmp store locations ]=== */
  47
  48 #define SPR_SHADOW_GPR(x)       ((x) + SPR_GPR_BASE + 32)
  49
  50 /*
  51  * emergency_print temporary stores
  52  */
  53 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
  54 #define EMERGENCY_PRINT_STORE_GPR4      l.mtspr r0,r4,SPR_SHADOW_GPR(14)
  55 #define EMERGENCY_PRINT_LOAD_GPR4       l.mfspr r4,r0,SPR_SHADOW_GPR(14)
  56
  57 #define EMERGENCY_PRINT_STORE_GPR5      l.mtspr r0,r5,SPR_SHADOW_GPR(15)
  58 #define EMERGENCY_PRINT_LOAD_GPR5       l.mfspr r5,r0,SPR_SHADOW_GPR(15)
  59
  60 #define EMERGENCY_PRINT_STORE_GPR6      l.mtspr r0,r6,SPR_SHADOW_GPR(16)
  61 #define EMERGENCY_PRINT_LOAD_GPR6       l.mfspr r6,r0,SPR_SHADOW_GPR(16)
  62
  63 #define EMERGENCY_PRINT_STORE_GPR7      l.mtspr r0,r7,SPR_SHADOW_GPR(7)
  64 #define EMERGENCY_PRINT_LOAD_GPR7       l.mfspr r7,r0,SPR_SHADOW_GPR(7)
  65
  66 #define EMERGENCY_PRINT_STORE_GPR8      l.mtspr r0,r8,SPR_SHADOW_GPR(8)
  67 #define EMERGENCY_PRINT_LOAD_GPR8       l.mfspr r8,r0,SPR_SHADOW_GPR(8)
  68
  69 #define EMERGENCY_PRINT_STORE_GPR9      l.mtspr r0,r9,SPR_SHADOW_GPR(9)
  70 #define EMERGENCY_PRINT_LOAD_GPR9       l.mfspr r9,r0,SPR_SHADOW_GPR(9)
  71
  72 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
  73 #define EMERGENCY_PRINT_STORE_GPR4      l.sw    0x20(r0),r4
  74 #define EMERGENCY_PRINT_LOAD_GPR4       l.lwz   r4,0x20(r0)
  75
  76 #define EMERGENCY_PRINT_STORE_GPR5      l.sw    0x24(r0),r5
  77 #define EMERGENCY_PRINT_LOAD_GPR5       l.lwz   r5,0x24(r0)
  78
  79 #define EMERGENCY_PRINT_STORE_GPR6      l.sw    0x28(r0),r6
  80 #define EMERGENCY_PRINT_LOAD_GPR6       l.lwz   r6,0x28(r0)
  81
  82 #define EMERGENCY_PRINT_STORE_GPR7      l.sw    0x2c(r0),r7
  83 #define EMERGENCY_PRINT_LOAD_GPR7       l.lwz   r7,0x2c(r0)
  84
  85 #define EMERGENCY_PRINT_STORE_GPR8      l.sw    0x30(r0),r8
  86 #define EMERGENCY_PRINT_LOAD_GPR8       l.lwz   r8,0x30(r0)
  87
  88 #define EMERGENCY_PRINT_STORE_GPR9      l.sw    0x34(r0),r9
  89 #define EMERGENCY_PRINT_LOAD_GPR9       l.lwz   r9,0x34(r0)
  90
  91 #endif
  92
  93 /*
  94  * TLB miss handlers temorary stores
  95  */
  96 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
  97 #define EXCEPTION_STORE_GPR2            l.mtspr r0,r2,SPR_SHADOW_GPR(2)
  98 #define EXCEPTION_LOAD_GPR2             l.mfspr r2,r0,SPR_SHADOW_GPR(2)
  99
 100 #define EXCEPTION_STORE_GPR3            l.mtspr r0,r3,SPR_SHADOW_GPR(3)
 101 #define EXCEPTION_LOAD_GPR3             l.mfspr r3,r0,SPR_SHADOW_GPR(3)
 102
 103 #define EXCEPTION_STORE_GPR4            l.mtspr r0,r4,SPR_SHADOW_GPR(4)
 104 #define EXCEPTION_LOAD_GPR4             l.mfspr r4,r0,SPR_SHADOW_GPR(4)
 105
 106 #define EXCEPTION_STORE_GPR5            l.mtspr r0,r5,SPR_SHADOW_GPR(5)
 107 #define EXCEPTION_LOAD_GPR5             l.mfspr r5,r0,SPR_SHADOW_GPR(5)
 108
 109 #define EXCEPTION_STORE_GPR6            l.mtspr r0,r6,SPR_SHADOW_GPR(6)
 110 #define EXCEPTION_LOAD_GPR6             l.mfspr r6,r0,SPR_SHADOW_GPR(6)
 111
 112 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
 113 #define EXCEPTION_STORE_GPR2            l.sw    0x64(r0),r2
 114 #define EXCEPTION_LOAD_GPR2             l.lwz   r2,0x64(r0)
 115
 116 #define EXCEPTION_STORE_GPR3            l.sw    0x68(r0),r3
 117 #define EXCEPTION_LOAD_GPR3             l.lwz   r3,0x68(r0)
 118
 119 #define EXCEPTION_STORE_GPR4            l.sw    0x6c(r0),r4
 120 #define EXCEPTION_LOAD_GPR4             l.lwz   r4,0x6c(r0)
 121
 122 #define EXCEPTION_STORE_GPR5            l.sw    0x70(r0),r5
 123 #define EXCEPTION_LOAD_GPR5             l.lwz   r5,0x70(r0)
 124
 125 #define EXCEPTION_STORE_GPR6            l.sw    0x74(r0),r6
 126 #define EXCEPTION_LOAD_GPR6             l.lwz   r6,0x74(r0)
 127
 128 #endif
 129
 130 /*
 131  * EXCEPTION_HANDLE temporary stores
 132  */
 133
 134 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
 135 #define EXCEPTION_T_STORE_GPR30         l.mtspr r0,r30,SPR_SHADOW_GPR(30)
 136 #define EXCEPTION_T_LOAD_GPR30(reg)     l.mfspr reg,r0,SPR_SHADOW_GPR(30)
 137
 138 #define EXCEPTION_T_STORE_GPR10         l.mtspr r0,r10,SPR_SHADOW_GPR(10)
 139 #define EXCEPTION_T_LOAD_GPR10(reg)     l.mfspr reg,r0,SPR_SHADOW_GPR(10)
 140
 141 #define EXCEPTION_T_STORE_SP            l.mtspr r0,r1,SPR_SHADOW_GPR(1)
 142 #define EXCEPTION_T_LOAD_SP(reg)        l.mfspr reg,r0,SPR_SHADOW_GPR(1)
 143
 144 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
 145 #define EXCEPTION_T_STORE_GPR30         l.sw    0x78(r0),r30
 146 #define EXCEPTION_T_LOAD_GPR30(reg)     l.lwz   reg,0x78(r0)
 147
 148 #define EXCEPTION_T_STORE_GPR10         l.sw    0x7c(r0),r10
 149 #define EXCEPTION_T_LOAD_GPR10(reg)     l.lwz   reg,0x7c(r0)
 150
 151 #define EXCEPTION_T_STORE_SP            l.sw    0x80(r0),r1
 152 #define EXCEPTION_T_LOAD_SP(reg)        l.lwz   reg,0x80(r0)
 153 #endif
 154
 155 /* =========================================================[ macros ]=== */
 156
 157 #ifdef CONFIG_SMP
 158 #define GET_CURRENT_PGD(reg,t1)                                 \
 159         LOAD_SYMBOL_2_GPR(reg,current_pgd)                      ;\
 160         l.mfspr t1,r0,SPR_COREID                                ;\
 161         l.slli  t1,t1,2                                         ;\
 162         l.add   reg,reg,t1                                      ;\
 163         tophys  (t1,reg)                                        ;\
 164         l.lwz   reg,0(t1)
 165 #else
 166 #define GET_CURRENT_PGD(reg,t1)                                 \
 167         LOAD_SYMBOL_2_GPR(reg,current_pgd)                      ;\
 168         tophys  (t1,reg)                                        ;\
 169         l.lwz   reg,0(t1)
 170 #endif
 171
 172 /* Load r10 from current_thread_info_set - clobbers r1 and r30 */
 173 #ifdef CONFIG_SMP
 174 #define GET_CURRENT_THREAD_INFO                                 \
 175         LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)           ;\
 176         tophys  (r30,r1)                                        ;\
 177         l.mfspr r10,r0,SPR_COREID                               ;\
 178         l.slli  r10,r10,2                                       ;\
 179         l.add   r30,r30,r10                                     ;\
 180         /* r10: current_thread_info  */                         ;\
 181         l.lwz   r10,0(r30)
 182 #else
 183 #define GET_CURRENT_THREAD_INFO                                 \
 184         LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)           ;\
 185         tophys  (r30,r1)                                        ;\
 186         /* r10: current_thread_info  */                         ;\
 187         l.lwz   r10,0(r30)
 188 #endif
 189
 190 /*
 191  * DSCR: this is a common hook for handling exceptions. it will save
 192  *       the needed registers, set up stack and pointer to current
 193  *       then jump to the handler while enabling MMU
 194  *
 195  * PRMS: handler        - a function to jump to. it has to save the
 196  *                      remaining registers to kernel stack, call
 197  *                      appropriate arch-independant exception handler
 198  *                      and finaly jump to ret_from_except
 199  *
 200  * PREQ: unchanged state from the time exception happened
 201  *
 202  * POST: SAVED the following registers original value
 203  *             to the new created exception frame pointed to by r1
 204  *
 205  *       r1  - ksp      pointing to the new (exception) frame
 206  *       r4  - EEAR     exception EA
 207  *       r10 - current  pointing to current_thread_info struct
 208  *       r12 - syscall  0, since we didn't come from syscall
 209  *       r30 - handler  address of the handler we'll jump to
 210  *
 211  *       handler has to save remaining registers to the exception
 212  *       ksp frame *before* tainting them!
 213  *
 214  * NOTE: this function is not reentrant per se. reentrancy is guaranteed
 215  *       by processor disabling all exceptions/interrupts when exception
 216  *       accours.
 217  *
 218  * OPTM: no need to make it so wasteful to extract ksp when in user mode
 219  */
 220
 221 #define EXCEPTION_HANDLE(handler)                               \
 222         EXCEPTION_T_STORE_GPR30                                 ;\
 223         l.mfspr r30,r0,SPR_ESR_BASE                             ;\
 224         l.andi  r30,r30,SPR_SR_SM                               ;\
 225         l.sfeqi r30,0                                           ;\
 226         EXCEPTION_T_STORE_GPR10                                 ;\
 227         l.bnf   2f                            /* kernel_mode */ ;\
 228          EXCEPTION_T_STORE_SP                 /* delay slot */  ;\
 229 1: /* user_mode:   */                                           ;\
 230         GET_CURRENT_THREAD_INFO                                 ;\
 231         tophys  (r30,r10)                                       ;\
 232         l.lwz   r1,(TI_KSP)(r30)                                ;\
 233         /* fall through */                                      ;\
 234 2: /* kernel_mode: */                                           ;\
 235         /* create new stack frame, save only needed gprs */     ;\
 236         /* r1: KSP, r10: current, r4: EEAR, r31: __pa(KSP) */   ;\
 237         /* r12: temp, syscall indicator */                      ;\
 238         l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 239         /* r1 is KSP, r30 is __pa(KSP) */                       ;\
 240         tophys  (r30,r1)                                        ;\
 241         l.sw    PT_GPR12(r30),r12                               ;\
 242         /* r4 use for tmp before EA */                          ;\
 243         l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 244         l.sw    PT_PC(r30),r12                                  ;\
 245         l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 246         l.sw    PT_SR(r30),r12                                  ;\
 247         /* save r30 */                                          ;\
 248         EXCEPTION_T_LOAD_GPR30(r12)                             ;\
 249         l.sw    PT_GPR30(r30),r12                               ;\
 250         /* save r10 as was prior to exception */                ;\
 251         EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 252         l.sw    PT_GPR10(r30),r12                               ;\
 253         /* save PT_SP as was prior to exception */              ;\
 254         EXCEPTION_T_LOAD_SP(r12)                                ;\
 255         l.sw    PT_SP(r30),r12                                  ;\
 256         /* save exception r4, set r4 = EA */                    ;\
 257         l.sw    PT_GPR4(r30),r4                                 ;\
 258         l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 259         /* r12 == 1 if we come from syscall */                  ;\
 260         CLEAR_GPR(r12)                                          ;\
 261         /* ----- turn on MMU ----- */                           ;\
 262         /* Carry DSX into exception SR */                       ;\
 263         l.mfspr r30,r0,SPR_SR                                   ;\
 264         l.andi  r30,r30,SPR_SR_DSX                              ;\
 265         l.ori   r30,r30,(EXCEPTION_SR)                          ;\
 266         l.mtspr r0,r30,SPR_ESR_BASE                             ;\
 267         /* r30: EA address of handler */                        ;\
 268         LOAD_SYMBOL_2_GPR(r30,handler)                          ;\
 269         l.mtspr r0,r30,SPR_EPCR_BASE                            ;\
 270         l.rfe
 271
 272 /*
 273  * this doesn't work
 274  *
 275  *
 276  * #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
 277  * #define UNHANDLED_EXCEPTION(handler)                         \
 278  *      l.ori   r3,r0,0x1                                       ;\
 279  *      l.mtspr r0,r3,SPR_SR                                    ;\
 280  *      l.movhi r3,hi(0xf0000100)                               ;\
 281  *      l.ori   r3,r3,lo(0xf0000100)                            ;\
 282  *      l.jr    r3                                              ;\
 283  *      l.nop   1
 284  *
 285  * #endif
 286  */
 287
 288 /* DSCR: this is the same as EXCEPTION_HANDLE(), we are just
 289  *       a bit more carefull (if we have a PT_SP or current pointer
 290  *       corruption) and set them up from 'current_set'
 291  *
 292  */
 293 #define UNHANDLED_EXCEPTION(handler)                            \
 294         EXCEPTION_T_STORE_GPR30                                 ;\
 295         EXCEPTION_T_STORE_GPR10                                 ;\
 296         EXCEPTION_T_STORE_SP                                    ;\
 297         /* temporary store r3, r9 into r1, r10 */               ;\
 298         l.addi  r1,r3,0x0                                       ;\
 299         l.addi  r10,r9,0x0                                      ;\
 300         LOAD_SYMBOL_2_GPR(r9,_string_unhandled_exception)       ;\
 301         tophys  (r3,r9)                                         ;\
 302         l.jal   _emergency_print                                ;\
 303          l.nop                                                  ;\
 304         l.mfspr r3,r0,SPR_NPC                                   ;\
 305         l.jal   _emergency_print_nr                             ;\
 306          l.andi r3,r3,0x1f00                                    ;\
 307         LOAD_SYMBOL_2_GPR(r9,_string_epc_prefix)                ;\
 308         tophys  (r3,r9)                                         ;\
 309         l.jal   _emergency_print                                ;\
 310          l.nop                                                  ;\
 311         l.jal   _emergency_print_nr                             ;\
 312          l.mfspr r3,r0,SPR_EPCR_BASE                            ;\
 313         LOAD_SYMBOL_2_GPR(r9,_string_nl)                        ;\
 314         tophys  (r3,r9)                                         ;\
 315         l.jal   _emergency_print                                ;\
 316          l.nop                                                  ;\
 317         /* end of printing */                                   ;\
 318         l.addi  r3,r1,0x0                                       ;\
 319         l.addi  r9,r10,0x0                                      ;\
 320         /* extract current, ksp from current_set */             ;\
 321         LOAD_SYMBOL_2_GPR(r1,_unhandled_stack_top)              ;\
 322         LOAD_SYMBOL_2_GPR(r10,init_thread_union)                ;\
 323         /* create new stack frame, save only needed gprs */     ;\
 324         /* r1: KSP, r10: current, r31: __pa(KSP) */             ;\
 325         /* r12: temp, syscall indicator, r13 temp */            ;\
 326         l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 327         /* r1 is KSP, r30 is __pa(KSP) */                       ;\
 328         tophys  (r30,r1)                                        ;\
 329         l.sw    PT_GPR12(r30),r12                                       ;\
 330         l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 331         l.sw    PT_PC(r30),r12                                  ;\
 332         l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 333         l.sw    PT_SR(r30),r12                                  ;\
 334         /* save r31 */                                          ;\
 335         EXCEPTION_T_LOAD_GPR30(r12)                             ;\
 336         l.sw    PT_GPR30(r30),r12                                       ;\
 337         /* save r10 as was prior to exception */                ;\
 338         EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 339         l.sw    PT_GPR10(r30),r12                                       ;\
 340         /* save PT_SP as was prior to exception */                      ;\
 341         EXCEPTION_T_LOAD_SP(r12)                                ;\
 342         l.sw    PT_SP(r30),r12                                  ;\
 343         l.sw    PT_GPR13(r30),r13                                       ;\
 344         /* --> */                                               ;\
 345         /* save exception r4, set r4 = EA */                    ;\
 346         l.sw    PT_GPR4(r30),r4                                 ;\
 347         l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 348         /* r12 == 1 if we come from syscall */                  ;\
 349         CLEAR_GPR(r12)                                          ;\
 350         /* ----- play a MMU trick ----- */                      ;\
 351         l.ori   r30,r0,(EXCEPTION_SR)                           ;\
 352         l.mtspr r0,r30,SPR_ESR_BASE                             ;\
 353         /* r31: EA address of handler */                        ;\
 354         LOAD_SYMBOL_2_GPR(r30,handler)                          ;\
 355         l.mtspr r0,r30,SPR_EPCR_BASE                            ;\
 356         l.rfe
 357
 358 /* =====================================================[ exceptions] === */
 359
 360 /* ---[ 0x100: RESET exception ]----------------------------------------- */
 361     .org 0x100
 362         /* Jump to .init code at _start which lives in the .head section
 363          * and will be discarded after boot.
 364          */
 365         LOAD_SYMBOL_2_GPR(r15, _start)
 366         tophys  (r13,r15)                       /* MMU disabled */
 367         l.jr    r13
 368          l.nop
 369
 370 /* ---[ 0x200: BUS exception ]------------------------------------------- */
 371     .org 0x200
 372 _dispatch_bus_fault:
 373         EXCEPTION_HANDLE(_bus_fault_handler)
 374
 375 /* ---[ 0x300: Data Page Fault exception ]------------------------------- */
 376     .org 0x300
 377 _dispatch_do_dpage_fault:
 378 //      totaly disable timer interrupt
 379 //      l.mtspr r0,r0,SPR_TTMR
 380 //      DEBUG_TLB_PROBE(0x300)
 381 //      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x300)
 382         EXCEPTION_HANDLE(_data_page_fault_handler)
 383
 384 /* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
 385     .org 0x400
 386 _dispatch_do_ipage_fault:
 387 //      totaly disable timer interrupt
 388 //      l.mtspr r0,r0,SPR_TTMR
 389 //      DEBUG_TLB_PROBE(0x400)
 390 //      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x400)
 391         EXCEPTION_HANDLE(_insn_page_fault_handler)
 392
 393 /* ---[ 0x500: Timer exception ]----------------------------------------- */
 394     .org 0x500
 395         EXCEPTION_HANDLE(_timer_handler)
 396
 397 /* ---[ 0x600: Alignment exception ]-------------------------------------- */
 398     .org 0x600
 399         EXCEPTION_HANDLE(_alignment_handler)
 400
 401 /* ---[ 0x700: Illegal insn exception ]---------------------------------- */
 402     .org 0x700
 403         EXCEPTION_HANDLE(_illegal_instruction_handler)
 404
 405 /* ---[ 0x800: External interrupt exception ]---------------------------- */
 406     .org 0x800
 407         EXCEPTION_HANDLE(_external_irq_handler)
 408
 409 /* ---[ 0x900: DTLB miss exception ]------------------------------------- */
 410     .org 0x900
 411         l.j     boot_dtlb_miss_handler
 412         l.nop
 413
 414 /* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
 415     .org 0xa00
 416         l.j     boot_itlb_miss_handler
 417         l.nop
 418
 419 /* ---[ 0xb00: Range exception ]----------------------------------------- */
 420     .org 0xb00
 421         UNHANDLED_EXCEPTION(_vector_0xb00)
 422
 423 /* ---[ 0xc00: Syscall exception ]--------------------------------------- */
 424     .org 0xc00
 425         EXCEPTION_HANDLE(_sys_call_handler)
 426
 427 /* ---[ 0xd00: Floating point exception ]--------------------------------- */
 428     .org 0xd00
 429         EXCEPTION_HANDLE(_fpe_trap_handler)
 430
 431 /* ---[ 0xe00: Trap exception ]------------------------------------------ */
 432     .org 0xe00
 433 //      UNHANDLED_EXCEPTION(_vector_0xe00)
 434         EXCEPTION_HANDLE(_trap_handler)
 435
 436 /* ---[ 0xf00: Reserved exception ]-------------------------------------- */
 437     .org 0xf00
 438         UNHANDLED_EXCEPTION(_vector_0xf00)
 439
 440 /* ---[ 0x1000: Reserved exception ]------------------------------------- */
 441     .org 0x1000
 442         UNHANDLED_EXCEPTION(_vector_0x1000)
 443
 444 /* ---[ 0x1100: Reserved exception ]------------------------------------- */
 445     .org 0x1100
 446         UNHANDLED_EXCEPTION(_vector_0x1100)
 447
 448 /* ---[ 0x1200: Reserved exception ]------------------------------------- */
 449     .org 0x1200
 450         UNHANDLED_EXCEPTION(_vector_0x1200)
 451
 452 /* ---[ 0x1300: Reserved exception ]------------------------------------- */
 453     .org 0x1300
 454         UNHANDLED_EXCEPTION(_vector_0x1300)
 455
 456 /* ---[ 0x1400: Reserved exception ]------------------------------------- */
 457     .org 0x1400
 458         UNHANDLED_EXCEPTION(_vector_0x1400)
 459
 460 /* ---[ 0x1500: Reserved exception ]------------------------------------- */
 461     .org 0x1500
 462         UNHANDLED_EXCEPTION(_vector_0x1500)
 463
 464 /* ---[ 0x1600: Reserved exception ]------------------------------------- */
 465     .org 0x1600
 466         UNHANDLED_EXCEPTION(_vector_0x1600)
 467
 468 /* ---[ 0x1700: Reserved exception ]------------------------------------- */
 469     .org 0x1700
 470         UNHANDLED_EXCEPTION(_vector_0x1700)
 471
 472 /* ---[ 0x1800: Reserved exception ]------------------------------------- */
 473     .org 0x1800
 474         UNHANDLED_EXCEPTION(_vector_0x1800)
 475
 476 /* ---[ 0x1900: Reserved exception ]------------------------------------- */
 477     .org 0x1900
 478         UNHANDLED_EXCEPTION(_vector_0x1900)
 479
 480 /* ---[ 0x1a00: Reserved exception ]------------------------------------- */
 481     .org 0x1a00
 482         UNHANDLED_EXCEPTION(_vector_0x1a00)
 483
 484 /* ---[ 0x1b00: Reserved exception ]------------------------------------- */
 485     .org 0x1b00
 486         UNHANDLED_EXCEPTION(_vector_0x1b00)
 487
 488 /* ---[ 0x1c00: Reserved exception ]------------------------------------- */
 489     .org 0x1c00
 490         UNHANDLED_EXCEPTION(_vector_0x1c00)
 491
 492 /* ---[ 0x1d00: Reserved exception ]------------------------------------- */
 493     .org 0x1d00
 494         UNHANDLED_EXCEPTION(_vector_0x1d00)
 495
 496 /* ---[ 0x1e00: Reserved exception ]------------------------------------- */
 497     .org 0x1e00
 498         UNHANDLED_EXCEPTION(_vector_0x1e00)
 499
 500 /* ---[ 0x1f00: Reserved exception ]------------------------------------- */
 501     .org 0x1f00
 502         UNHANDLED_EXCEPTION(_vector_0x1f00)
 503
 504     .org 0x2000
 505 /* ===================================================[ kernel start ]=== */
 506
 507 /*    .text*/
 508
 509 /* This early stuff belongs in HEAD, but some of the functions below definitely
 510  * don't... */
 511
 512         __HEAD
 513         .global _start
 514 _start:
 515         /* Init r0 to zero as per spec */
 516         CLEAR_GPR(r0)
 517
 518         /* save kernel parameters */
 519         l.or    r25,r0,r3       /* pointer to fdt */
 520
 521         /*
 522          * ensure a deterministic start
 523          */
 524
 525         l.ori   r3,r0,0x1
 526         l.mtspr r0,r3,SPR_SR
 527
 528         /*
 529          * Start the TTCR as early as possible, so that the RNG can make use of
 530          * measurements of boot time from the earliest opportunity. Especially
 531          * important is that the TTCR does not return zero by the time we reach
 532          * random_init().
 533          */
 534         l.movhi r3,hi(SPR_TTMR_CR)
 535         l.mtspr r0,r3,SPR_TTMR
 536
 537         CLEAR_GPR(r1)
 538         CLEAR_GPR(r2)
 539         CLEAR_GPR(r3)
 540         CLEAR_GPR(r4)
 541         CLEAR_GPR(r5)
 542         CLEAR_GPR(r6)
 543         CLEAR_GPR(r7)
 544         CLEAR_GPR(r8)
 545         CLEAR_GPR(r9)
 546         CLEAR_GPR(r10)
 547         CLEAR_GPR(r11)
 548         CLEAR_GPR(r12)
 549         CLEAR_GPR(r13)
 550         CLEAR_GPR(r14)
 551         CLEAR_GPR(r15)
 552         CLEAR_GPR(r16)
 553         CLEAR_GPR(r17)
 554         CLEAR_GPR(r18)
 555         CLEAR_GPR(r19)
 556         CLEAR_GPR(r20)
 557         CLEAR_GPR(r21)
 558         CLEAR_GPR(r22)
 559         CLEAR_GPR(r23)
 560         CLEAR_GPR(r24)
 561         CLEAR_GPR(r26)
 562         CLEAR_GPR(r27)
 563         CLEAR_GPR(r28)
 564         CLEAR_GPR(r29)
 565         CLEAR_GPR(r30)
 566         CLEAR_GPR(r31)
 567
 568 #ifdef CONFIG_SMP
 569         l.mfspr r26,r0,SPR_COREID
 570         l.sfeq  r26,r0
 571         l.bnf   secondary_wait
 572          l.nop
 573 #endif
 574         /*
 575          * set up initial ksp and current
 576          */
 577         /* setup kernel stack */
 578         LOAD_SYMBOL_2_GPR(r1,init_thread_union + THREAD_SIZE)
 579         LOAD_SYMBOL_2_GPR(r10,init_thread_union)        // setup current
 580         tophys  (r31,r10)
 581         l.sw    TI_KSP(r31), r1
 582
 583         l.ori   r4,r0,0x0
 584
 585
 586         /*
 587          * .data contains initialized data,
 588          * .bss contains uninitialized data - clear it up
 589          */
 590 clear_bss:
 591         LOAD_SYMBOL_2_GPR(r24, __bss_start)
 592         LOAD_SYMBOL_2_GPR(r26, _end)
 593         tophys(r28,r24)
 594         tophys(r30,r26)
 595         CLEAR_GPR(r24)
 596         CLEAR_GPR(r26)
 597 1:
 598         l.sw    (0)(r28),r0
 599         l.sfltu r28,r30
 600         l.bf    1b
 601         l.addi  r28,r28,4
 602
 603 enable_ic:
 604         l.jal   _ic_enable
 605          l.nop
 606
 607 enable_dc:
 608         l.jal   _dc_enable
 609          l.nop
 610
 611 flush_tlb:
 612         l.jal   _flush_tlb
 613          l.nop
 614
 615 /* The MMU needs to be enabled before or1k_early_setup is called */
 616
 617 enable_mmu:
 618         /*
 619          * enable dmmu & immu
 620          * SR[5] = 0, SR[6] = 0, 6th and 7th bit of SR set to 0
 621          */
 622         l.mfspr r30,r0,SPR_SR
 623         l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
 624         l.ori   r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 625         l.or    r30,r30,r28
 626         l.mtspr r0,r30,SPR_SR
 627         l.nop
 628         l.nop
 629         l.nop
 630         l.nop
 631         l.nop
 632         l.nop
 633         l.nop
 634         l.nop
 635         l.nop
 636         l.nop
 637         l.nop
 638         l.nop
 639         l.nop
 640         l.nop
 641         l.nop
 642         l.nop
 643
 644         // reset the simulation counters
 645         l.nop 5
 646
 647         /* check fdt header magic word */
 648         l.lwz   r3,0(r25)       /* load magic from fdt into r3 */
 649         l.movhi r4,hi(OF_DT_HEADER)
 650         l.ori   r4,r4,lo(OF_DT_HEADER)
 651         l.sfeq  r3,r4
 652         l.bf    _fdt_found
 653          l.nop
 654         /* magic number mismatch, set fdt pointer to null */
 655         l.or    r25,r0,r0
 656 _fdt_found:
 657         /* pass fdt pointer to or1k_early_setup in r3 */
 658         l.or    r3,r0,r25
 659         LOAD_SYMBOL_2_GPR(r24, or1k_early_setup)
 660         l.jalr r24
 661          l.nop
 662
 663 clear_regs:
 664         /*
 665          * clear all GPRS to increase determinism
 666          */
 667         CLEAR_GPR(r2)
 668         CLEAR_GPR(r3)
 669         CLEAR_GPR(r4)
 670         CLEAR_GPR(r5)
 671         CLEAR_GPR(r6)
 672         CLEAR_GPR(r7)
 673         CLEAR_GPR(r8)
 674         CLEAR_GPR(r9)
 675         CLEAR_GPR(r11)
 676         CLEAR_GPR(r12)
 677         CLEAR_GPR(r13)
 678         CLEAR_GPR(r14)
 679         CLEAR_GPR(r15)
 680         CLEAR_GPR(r16)
 681         CLEAR_GPR(r17)
 682         CLEAR_GPR(r18)
 683         CLEAR_GPR(r19)
 684         CLEAR_GPR(r20)
 685         CLEAR_GPR(r21)
 686         CLEAR_GPR(r22)
 687         CLEAR_GPR(r23)
 688         CLEAR_GPR(r24)
 689         CLEAR_GPR(r25)
 690         CLEAR_GPR(r26)
 691         CLEAR_GPR(r27)
 692         CLEAR_GPR(r28)
 693         CLEAR_GPR(r29)
 694         CLEAR_GPR(r30)
 695         CLEAR_GPR(r31)
 696
 697 jump_start_kernel:
 698         /*
 699          * jump to kernel entry (start_kernel)
 700          */
 701         LOAD_SYMBOL_2_GPR(r30, start_kernel)
 702         l.jr    r30
 703          l.nop
 704
 705 _flush_tlb:
 706         /*
 707          *  I N V A L I D A T E   T L B   e n t r i e s
 708          */
 709         LOAD_SYMBOL_2_GPR(r5,SPR_DTLBMR_BASE(0))
 710         LOAD_SYMBOL_2_GPR(r6,SPR_ITLBMR_BASE(0))
 711         l.addi  r7,r0,128 /* Maximum number of sets */
 712 1:
 713         l.mtspr r5,r0,0x0
 714         l.mtspr r6,r0,0x0
 715
 716         l.addi  r5,r5,1
 717         l.addi  r6,r6,1
 718         l.sfeq  r7,r0
 719         l.bnf   1b
 720          l.addi r7,r7,-1
 721
 722         l.jr    r9
 723          l.nop
 724
 725 #ifdef CONFIG_SMP
 726 secondary_wait:
 727         /* Doze the cpu until we are asked to run */
 728         /* If we dont have power management skip doze */
 729         l.mfspr r25,r0,SPR_UPR
 730         l.andi  r25,r25,SPR_UPR_PMP
 731         l.sfeq  r25,r0
 732         l.bf    secondary_check_release
 733          l.nop
 734
 735         /* Setup special secondary exception handler */
 736         LOAD_SYMBOL_2_GPR(r3, _secondary_evbar)
 737         tophys(r25,r3)
 738         l.mtspr r0,r25,SPR_EVBAR
 739
 740         /* Enable Interrupts */
 741         l.mfspr r25,r0,SPR_SR
 742         l.ori   r25,r25,SPR_SR_IEE
 743         l.mtspr r0,r25,SPR_SR
 744
 745         /* Unmask interrupts interrupts */
 746         l.mfspr r25,r0,SPR_PICMR
 747         l.ori   r25,r25,0xffff
 748         l.mtspr r0,r25,SPR_PICMR
 749
 750         /* Doze */
 751         l.mfspr r25,r0,SPR_PMR
 752         LOAD_SYMBOL_2_GPR(r3, SPR_PMR_DME)
 753         l.or    r25,r25,r3
 754         l.mtspr r0,r25,SPR_PMR
 755
 756         /* Wakeup - Restore exception handler */
 757         l.mtspr r0,r0,SPR_EVBAR
 758
 759 secondary_check_release:
 760         /*
 761          * Check if we actually got the release signal, if not go-back to
 762          * sleep.
 763          */
 764         l.mfspr r25,r0,SPR_COREID
 765         LOAD_SYMBOL_2_GPR(r3, secondary_release)
 766         tophys(r4, r3)
 767         l.lwz   r3,0(r4)
 768         l.sfeq  r25,r3
 769         l.bnf   secondary_wait
 770          l.nop
 771         /* fall through to secondary_init */
 772
 773 secondary_init:
 774         /*
 775          * set up initial ksp and current
 776          */
 777         LOAD_SYMBOL_2_GPR(r10, secondary_thread_info)
 778         tophys  (r30,r10)
 779         l.lwz   r10,0(r30)
 780         l.addi  r1,r10,THREAD_SIZE
 781         tophys  (r30,r10)
 782         l.sw    TI_KSP(r30),r1
 783
 784         l.jal   _ic_enable
 785          l.nop
 786
 787         l.jal   _dc_enable
 788          l.nop
 789
 790         l.jal   _flush_tlb
 791          l.nop
 792
 793         /*
 794          * enable dmmu & immu
 795          */
 796         l.mfspr r30,r0,SPR_SR
 797         l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
 798         l.ori   r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 799         l.or    r30,r30,r28
 800         /*
 801          * This is a bit tricky, we need to switch over from physical addresses
 802          * to virtual addresses on the fly.
 803          * To do that, we first set up ESR with the IME and DME bits set.
 804          * Then EPCR is set to secondary_start and then a l.rfe is issued to
 805          * "jump" to that.
 806          */
 807         l.mtspr r0,r30,SPR_ESR_BASE
 808         LOAD_SYMBOL_2_GPR(r30, secondary_start)
 809         l.mtspr r0,r30,SPR_EPCR_BASE
 810         l.rfe
 811
 812 secondary_start:
 813         LOAD_SYMBOL_2_GPR(r30, secondary_start_kernel)
 814         l.jr    r30
 815          l.nop
 816
 817 #endif
 818
 819 /* ========================================[ cache ]=== */
 820
 821         /* alignment here so we don't change memory offsets with
 822          * memory controller defined
 823          */
 824         .align 0x2000
 825
 826 _ic_enable:
 827         /* Check if IC present and skip enabling otherwise */
 828         l.mfspr r24,r0,SPR_UPR
 829         l.andi  r26,r24,SPR_UPR_ICP
 830         l.sfeq  r26,r0
 831         l.bf    9f
 832         l.nop
 833
 834         /* Disable IC */
 835         l.mfspr r6,r0,SPR_SR
 836         l.addi  r5,r0,-1
 837         l.xori  r5,r5,SPR_SR_ICE
 838         l.and   r5,r6,r5
 839         l.mtspr r0,r5,SPR_SR
 840
 841         /* Establish cache block size
 842            If BS=0, 16;
 843            If BS=1, 32;
 844            r14 contain block size
 845         */
 846         l.mfspr r24,r0,SPR_ICCFGR
 847         l.andi  r26,r24,SPR_ICCFGR_CBS
 848         l.srli  r28,r26,7
 849         l.ori   r30,r0,16
 850         l.sll   r14,r30,r28
 851
 852         /* Establish number of cache sets
 853            r16 contains number of cache sets
 854            r28 contains log(# of cache sets)
 855         */
 856         l.andi  r26,r24,SPR_ICCFGR_NCS
 857         l.srli  r28,r26,3
 858         l.ori   r30,r0,1
 859         l.sll   r16,r30,r28
 860
 861         /* Invalidate IC */
 862         l.addi  r6,r0,0
 863         l.sll   r5,r14,r28
 864 //        l.mul   r5,r14,r16
 865 //      l.trap  1
 866 //      l.addi  r5,r0,IC_SIZE
 867 1:
 868         l.mtspr r0,r6,SPR_ICBIR
 869         l.sfne  r6,r5
 870         l.bf    1b
 871         l.add   r6,r6,r14
 872  //       l.addi   r6,r6,IC_LINE
 873
 874         /* Enable IC */
 875         l.mfspr r6,r0,SPR_SR
 876         l.ori   r6,r6,SPR_SR_ICE
 877         l.mtspr r0,r6,SPR_SR
 878         l.nop
 879         l.nop
 880         l.nop
 881         l.nop
 882         l.nop
 883         l.nop
 884         l.nop
 885         l.nop
 886         l.nop
 887         l.nop
 888 9:
 889         l.jr    r9
 890         l.nop
 891
 892 _dc_enable:
 893         /* Check if DC present and skip enabling otherwise */
 894         l.mfspr r24,r0,SPR_UPR
 895         l.andi  r26,r24,SPR_UPR_DCP
 896         l.sfeq  r26,r0
 897         l.bf    9f
 898         l.nop
 899
 900         /* Disable DC */
 901         l.mfspr r6,r0,SPR_SR
 902         l.addi  r5,r0,-1
 903         l.xori  r5,r5,SPR_SR_DCE
 904         l.and   r5,r6,r5
 905         l.mtspr r0,r5,SPR_SR
 906
 907         /* Establish cache block size
 908            If BS=0, 16;
 909            If BS=1, 32;
 910            r14 contain block size
 911         */
 912         l.mfspr r24,r0,SPR_DCCFGR
 913         l.andi  r26,r24,SPR_DCCFGR_CBS
 914         l.srli  r28,r26,7
 915         l.ori   r30,r0,16
 916         l.sll   r14,r30,r28
 917
 918         /* Establish number of cache sets
 919            r16 contains number of cache sets
 920            r28 contains log(# of cache sets)
 921         */
 922         l.andi  r26,r24,SPR_DCCFGR_NCS
 923         l.srli  r28,r26,3
 924         l.ori   r30,r0,1
 925         l.sll   r16,r30,r28
 926
 927         /* Invalidate DC */
 928         l.addi  r6,r0,0
 929         l.sll   r5,r14,r28
 930 1:
 931         l.mtspr r0,r6,SPR_DCBIR
 932         l.sfne  r6,r5
 933         l.bf    1b
 934         l.add   r6,r6,r14
 935
 936         /* Enable DC */
 937         l.mfspr r6,r0,SPR_SR
 938         l.ori   r6,r6,SPR_SR_DCE
 939         l.mtspr r0,r6,SPR_SR
 940 9:
 941         l.jr    r9
 942         l.nop
 943
 944 /* ===============================================[ page table masks ]=== */
 945
 946 #define DTLB_UP_CONVERT_MASK  0x3fa
 947 #define ITLB_UP_CONVERT_MASK  0x3a
 948
 949 /* for SMP we'd have (this is a bit subtle, CC must be always set
 950  * for SMP, but since we have _PAGE_PRESENT bit always defined
 951  * we can just modify the mask)
 952  */
 953 #define DTLB_SMP_CONVERT_MASK  0x3fb
 954 #define ITLB_SMP_CONVERT_MASK  0x3b
 955
 956 /* ---[ boot dtlb miss handler ]----------------------------------------- */
 957
 958 boot_dtlb_miss_handler:
 959
 960 /* mask for DTLB_MR register: - (0) sets V (valid) bit,
 961  *                            - (31-12) sets bits belonging to VPN (31-12)
 962  */
 963 #define DTLB_MR_MASK 0xfffff001
 964
 965 /* mask for DTLB_TR register: - (2) sets CI (cache inhibit) bit,
 966  *                            - (4) sets A (access) bit,
 967  *                            - (5) sets D (dirty) bit,
 968  *                            - (8) sets SRE (superuser read) bit
 969  *                            - (9) sets SWE (superuser write) bit
 970  *                            - (31-12) sets bits belonging to VPN (31-12)
 971  */
 972 #define DTLB_TR_MASK 0xfffff332
 973
 974 /* These are for masking out the VPN/PPN value from the MR/TR registers...
 975  * it's not the same as the PFN */
 976 #define VPN_MASK 0xfffff000
 977 #define PPN_MASK 0xfffff000
 978
 979
 980         EXCEPTION_STORE_GPR6
 981
 982 #if 0
 983         l.mfspr r6,r0,SPR_ESR_BASE         //
 984         l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
 985         l.sfeqi r6,0                       // r6 == 0x1 --> SM
 986         l.bf    exit_with_no_dtranslation  //
 987         l.nop
 988 #endif
 989
 990         /* this could be optimized by moving storing of
 991          * non r6 registers here, and jumping r6 restore
 992          * if not in supervisor mode
 993          */
 994
 995         EXCEPTION_STORE_GPR2
 996         EXCEPTION_STORE_GPR3
 997         EXCEPTION_STORE_GPR4
 998         EXCEPTION_STORE_GPR5
 999
1000         l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
1001
1002 immediate_translation:
1003         CLEAR_GPR(r6)
1004
1005         l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
1006
1007         l.mfspr r6, r0, SPR_DMMUCFGR
1008         l.andi  r6, r6, SPR_DMMUCFGR_NTS
1009         l.srli  r6, r6, SPR_DMMUCFGR_NTS_OFF
1010         l.ori   r5, r0, 0x1
1011         l.sll   r5, r5, r6      // r5 = number DMMU sets
1012         l.addi  r6, r5, -1      // r6 = nsets mask
1013         l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
1014
1015         l.or    r6,r6,r4                   // r6 <- r4
1016         l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
1017         l.movhi r5,hi(DTLB_MR_MASK)        // r5 <- ffff:0000.x000
1018         l.ori   r5,r5,lo(DTLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply DTLB_MR_MASK
1019         l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have DTLBMR entry
1020         l.mtspr r2,r5,SPR_DTLBMR_BASE(0)   // set DTLBMR
1021
1022         /* set up DTLB with no translation for EA <= 0xbfffffff */
1023         LOAD_SYMBOL_2_GPR(r6,0xbfffffff)
1024         l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xbfffffff >= EA)
1025         l.bf     1f                        // goto out
1026         l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
1027
1028         tophys(r3,r4)                      // r3 <- PA
1029 1:
1030         l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
1031         l.movhi r5,hi(DTLB_TR_MASK)        // r5 <- ffff:0000.x000
1032         l.ori   r5,r5,lo(DTLB_TR_MASK)     // r5 <- ffff:1111.x330 - apply DTLB_MR_MASK
1033         l.and   r5,r5,r3                   // r5 <- PPN :PPN .x330 - we have DTLBTR entry
1034         l.mtspr r2,r5,SPR_DTLBTR_BASE(0)   // set DTLBTR
1035
1036         EXCEPTION_LOAD_GPR6
1037         EXCEPTION_LOAD_GPR5
1038         EXCEPTION_LOAD_GPR4
1039         EXCEPTION_LOAD_GPR3
1040         EXCEPTION_LOAD_GPR2
1041
1042         l.rfe                              // SR <- ESR, PC <- EPC
1043
1044 exit_with_no_dtranslation:
1045         /* EA out of memory or not in supervisor mode */
1046         EXCEPTION_LOAD_GPR6
1047         EXCEPTION_LOAD_GPR4
1048         l.j     _dispatch_bus_fault
1049
1050 /* ---[ boot itlb miss handler ]----------------------------------------- */
1051
1052 boot_itlb_miss_handler:
1053
1054 /* mask for ITLB_MR register: - sets V (valid) bit,
1055  *                            - sets bits belonging to VPN (15-12)
1056  */
1057 #define ITLB_MR_MASK 0xfffff001
1058
1059 /* mask for ITLB_TR register: - sets A (access) bit,
1060  *                            - sets SXE (superuser execute) bit
1061  *                            - sets bits belonging to VPN (15-12)
1062  */
1063 #define ITLB_TR_MASK 0xfffff050
1064
1065 /*
1066 #define VPN_MASK 0xffffe000
1067 #define PPN_MASK 0xffffe000
1068 */
1069
1070
1071
1072         EXCEPTION_STORE_GPR2
1073         EXCEPTION_STORE_GPR3
1074         EXCEPTION_STORE_GPR4
1075         EXCEPTION_STORE_GPR5
1076         EXCEPTION_STORE_GPR6
1077
1078 #if 0
1079         l.mfspr r6,r0,SPR_ESR_BASE         //
1080         l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
1081         l.sfeqi r6,0                       // r6 == 0x1 --> SM
1082         l.bf    exit_with_no_itranslation
1083         l.nop
1084 #endif
1085
1086
1087         l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
1088
1089 earlyearly:
1090         CLEAR_GPR(r6)
1091
1092         l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
1093
1094         l.mfspr r6, r0, SPR_IMMUCFGR
1095         l.andi  r6, r6, SPR_IMMUCFGR_NTS
1096         l.srli  r6, r6, SPR_IMMUCFGR_NTS_OFF
1097         l.ori   r5, r0, 0x1
1098         l.sll   r5, r5, r6      // r5 = number IMMU sets from IMMUCFGR
1099         l.addi  r6, r5, -1      // r6 = nsets mask
1100         l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
1101
1102         l.or    r6,r6,r4                   // r6 <- r4
1103         l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
1104         l.movhi r5,hi(ITLB_MR_MASK)        // r5 <- ffff:0000.x000
1105         l.ori   r5,r5,lo(ITLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply ITLB_MR_MASK
1106         l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have ITLBMR entry
1107         l.mtspr r2,r5,SPR_ITLBMR_BASE(0)   // set ITLBMR
1108
1109         /*
1110          * set up ITLB with no translation for EA <= 0x0fffffff
1111          *
1112          * we need this for head.S mapping (EA = PA). if we move all functions
1113          * which run with mmu enabled into entry.S, we might be able to eliminate this.
1114          *
1115          */
1116         LOAD_SYMBOL_2_GPR(r6,0x0fffffff)
1117         l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xb0ffffff >= EA)
1118         l.bf     1f                        // goto out
1119         l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
1120
1121         tophys(r3,r4)                      // r3 <- PA
1122 1:
1123         l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
1124         l.movhi r5,hi(ITLB_TR_MASK)        // r5 <- ffff:0000.x000
1125         l.ori   r5,r5,lo(ITLB_TR_MASK)     // r5 <- ffff:1111.x050 - apply ITLB_MR_MASK
1126         l.and   r5,r5,r3                   // r5 <- PPN :PPN .x050 - we have ITLBTR entry
1127         l.mtspr r2,r5,SPR_ITLBTR_BASE(0)   // set ITLBTR
1128
1129         EXCEPTION_LOAD_GPR6
1130         EXCEPTION_LOAD_GPR5
1131         EXCEPTION_LOAD_GPR4
1132         EXCEPTION_LOAD_GPR3
1133         EXCEPTION_LOAD_GPR2
1134
1135         l.rfe                              // SR <- ESR, PC <- EPC
1136
1137 exit_with_no_itranslation:
1138         EXCEPTION_LOAD_GPR4
1139         EXCEPTION_LOAD_GPR6
1140         l.j    _dispatch_bus_fault
1141         l.nop
1142
1143 /* ====================================================================== */
1144 /*
1145  * Stuff below here shouldn't go into .head section... maybe this stuff
1146  * can be moved to entry.S ???
1147  */
1148
1149 /* ==============================================[ DTLB miss handler ]=== */
1150
1151 /*
1152  * Comments:
1153  *   Exception handlers are entered with MMU off so the following handler
1154  *   needs to use physical addressing
1155  *
1156  */
1157
1158         .text
1159 ENTRY(dtlb_miss_handler)
1160         EXCEPTION_STORE_GPR2
1161         EXCEPTION_STORE_GPR3
1162         EXCEPTION_STORE_GPR4
1163         /*
1164          * get EA of the miss
1165          */
1166         l.mfspr r2,r0,SPR_EEAR_BASE
1167         /*
1168          * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1169          */
1170         GET_CURRENT_PGD(r3,r4)          // r3 is current_pgd, r4 is temp
1171         l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1172         l.slli  r4,r4,0x2               // to get address << 2
1173         l.add   r3,r4,r3                // r4 is pgd_index(daddr)
1174         /*
1175          * if (pmd_none(*pmd))
1176          *   goto pmd_none:
1177          */
1178         tophys  (r4,r3)
1179         l.lwz   r3,0x0(r4)              // get *pmd value
1180         l.sfne  r3,r0
1181         l.bnf   d_pmd_none
1182          l.addi r3,r0,0xffffe000        // PAGE_MASK
1183
1184 d_pmd_good:
1185         /*
1186          * pte = *pte_offset(pmd, daddr);
1187          */
1188         l.lwz   r4,0x0(r4)              // get **pmd value
1189         l.and   r4,r4,r3                // & PAGE_MASK
1190         l.srli  r2,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1191         l.andi  r3,r2,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1192         l.slli  r3,r3,0x2               // to get address << 2
1193         l.add   r3,r3,r4
1194         l.lwz   r3,0x0(r3)              // this is pte at last
1195         /*
1196          * if (!pte_present(pte))
1197          */
1198         l.andi  r4,r3,0x1
1199         l.sfne  r4,r0                   // is pte present
1200         l.bnf   d_pte_not_present
1201         l.addi  r4,r0,0xffffe3fa        // PAGE_MASK | DTLB_UP_CONVERT_MASK
1202         /*
1203          * fill DTLB TR register
1204          */
1205         l.and   r4,r3,r4                // apply the mask
1206         // Determine number of DMMU sets
1207         l.mfspr r2, r0, SPR_DMMUCFGR
1208         l.andi  r2, r2, SPR_DMMUCFGR_NTS
1209         l.srli  r2, r2, SPR_DMMUCFGR_NTS_OFF
1210         l.ori   r3, r0, 0x1
1211         l.sll   r3, r3, r2      // r3 = number DMMU sets DMMUCFGR
1212         l.addi  r2, r3, -1      // r2 = nsets mask
1213         l.mfspr r3, r0, SPR_EEAR_BASE
1214         l.srli  r3, r3, 0xd     // >> PAGE_SHIFT
1215         l.and   r2, r3, r2      // calc offset:  & (NUM_TLB_ENTRIES-1)
1216                                                            //NUM_TLB_ENTRIES
1217         l.mtspr r2,r4,SPR_DTLBTR_BASE(0)
1218         /*
1219          * fill DTLB MR register
1220          */
1221         l.slli  r3, r3, 0xd             /* << PAGE_SHIFT => EA & PAGE_MASK */
1222         l.ori   r4,r3,0x1               // set hardware valid bit: DTBL_MR entry
1223         l.mtspr r2,r4,SPR_DTLBMR_BASE(0)
1224
1225         EXCEPTION_LOAD_GPR2
1226         EXCEPTION_LOAD_GPR3
1227         EXCEPTION_LOAD_GPR4
1228         l.rfe
1229 d_pmd_none:
1230 d_pte_not_present:
1231         EXCEPTION_LOAD_GPR2
1232         EXCEPTION_LOAD_GPR3
1233         EXCEPTION_LOAD_GPR4
1234         EXCEPTION_HANDLE(_dtlb_miss_page_fault_handler)
1235
1236 /* ==============================================[ ITLB miss handler ]=== */
1237 ENTRY(itlb_miss_handler)
1238         EXCEPTION_STORE_GPR2
1239         EXCEPTION_STORE_GPR3
1240         EXCEPTION_STORE_GPR4
1241         /*
1242          * get EA of the miss
1243          */
1244         l.mfspr r2,r0,SPR_EEAR_BASE
1245
1246         /*
1247          * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1248          *
1249          */
1250         GET_CURRENT_PGD(r3,r4)          // r3 is current_pgd, r5 is temp
1251         l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1252         l.slli  r4,r4,0x2               // to get address << 2
1253         l.add   r3,r4,r3                // r4 is pgd_index(daddr)
1254         /*
1255          * if (pmd_none(*pmd))
1256          *   goto pmd_none:
1257          */
1258         tophys  (r4,r3)
1259         l.lwz   r3,0x0(r4)              // get *pmd value
1260         l.sfne  r3,r0
1261         l.bnf   i_pmd_none
1262          l.addi r3,r0,0xffffe000        // PAGE_MASK
1263
1264 i_pmd_good:
1265         /*
1266          * pte = *pte_offset(pmd, iaddr);
1267          *
1268          */
1269         l.lwz   r4,0x0(r4)              // get **pmd value
1270         l.and   r4,r4,r3                // & PAGE_MASK
1271         l.srli  r2,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1272         l.andi  r3,r2,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1273         l.slli  r3,r3,0x2               // to get address << 2
1274         l.add   r3,r3,r4
1275         l.lwz   r3,0x0(r3)              // this is pte at last
1276         /*
1277          * if (!pte_present(pte))
1278          *
1279          */
1280         l.andi  r4,r3,0x1
1281         l.sfne  r4,r0                   // is pte present
1282         l.bnf   i_pte_not_present
1283          l.addi r4,r0,0xffffe03a        // PAGE_MASK | ITLB_UP_CONVERT_MASK
1284         /*
1285          * fill ITLB TR register
1286          */
1287         l.and   r4,r3,r4                // apply the mask
1288         l.andi  r3,r3,0x7c0             // _PAGE_EXEC | _PAGE_SRE | _PAGE_SWE |  _PAGE_URE | _PAGE_UWE
1289         l.sfeq  r3,r0
1290         l.bf    itlb_tr_fill //_workaround
1291         // Determine number of IMMU sets
1292         l.mfspr r2, r0, SPR_IMMUCFGR
1293         l.andi  r2, r2, SPR_IMMUCFGR_NTS
1294         l.srli  r2, r2, SPR_IMMUCFGR_NTS_OFF
1295         l.ori   r3, r0, 0x1
1296         l.sll   r3, r3, r2      // r3 = number IMMU sets IMMUCFGR
1297         l.addi  r2, r3, -1      // r2 = nsets mask
1298         l.mfspr r3, r0, SPR_EEAR_BASE
1299         l.srli  r3, r3, 0xd     // >> PAGE_SHIFT
1300         l.and   r2, r3, r2      // calc offset:  & (NUM_TLB_ENTRIES-1)
1301
1302 /*
1303  * __PHX__ :: fixme
1304  * we should not just blindly set executable flags,
1305  * but it does help with ping. the clean way would be to find out
1306  * (and fix it) why stack doesn't have execution permissions
1307  */
1308
1309 itlb_tr_fill_workaround:
1310         l.ori   r4,r4,0xc0              // | (SPR_ITLBTR_UXE | ITLBTR_SXE)
1311 itlb_tr_fill:
1312         l.mtspr r2,r4,SPR_ITLBTR_BASE(0)
1313         /*
1314          * fill DTLB MR register
1315          */
1316         l.slli  r3, r3, 0xd             /* << PAGE_SHIFT => EA & PAGE_MASK */
1317         l.ori   r4,r3,0x1               // set hardware valid bit: ITBL_MR entry
1318         l.mtspr r2,r4,SPR_ITLBMR_BASE(0)
1319
1320         EXCEPTION_LOAD_GPR2
1321         EXCEPTION_LOAD_GPR3
1322         EXCEPTION_LOAD_GPR4
1323         l.rfe
1324
1325 i_pmd_none:
1326 i_pte_not_present:
1327         EXCEPTION_LOAD_GPR2
1328         EXCEPTION_LOAD_GPR3
1329         EXCEPTION_LOAD_GPR4
1330         EXCEPTION_HANDLE(_itlb_miss_page_fault_handler)
1331
1332 /* ==============================================[ boot tlb handlers ]=== */
1333
1334
1335 /* =================================================[ debugging aids ]=== */
1336
1337 /*
1338  * DESC: Prints ASCII character stored in r7
1339  *
1340  * PRMS: r7     - a 32-bit value with an ASCII character in the first byte
1341  *              position.
1342  *
1343  * PREQ: The UART at UART_BASE_ADD has to be initialized
1344  *
1345  * POST: internally used but restores:
1346  *       r4     - to store UART_BASE_ADD
1347  *       r5     - for loading OFF_TXFULL / THRE,TEMT
1348  *       r6     - for storing bitmask (SERIAL_8250)
1349  */
1350 ENTRY(_emergency_putc)
1351         EMERGENCY_PRINT_STORE_GPR4
1352         EMERGENCY_PRINT_STORE_GPR5
1353         EMERGENCY_PRINT_STORE_GPR6
1354
1355         l.movhi r4,hi(UART_BASE_ADD)
1356         l.ori   r4,r4,lo(UART_BASE_ADD)
1357
1358 #if defined(CONFIG_SERIAL_LITEUART)
1359         /* Check OFF_TXFULL status */
1360 1:      l.lwz   r5,4(r4)
1361         l.andi  r5,r5,0xff
1362         l.sfnei r5,0
1363         l.bf    1b
1364          l.nop
1365
1366         /* Write character */
1367         l.andi  r7,r7,0xff
1368         l.sw    0(r4),r7
1369 #elif defined(CONFIG_SERIAL_8250)
1370         /* Check UART LSR THRE (hold) bit */
1371         l.addi  r6,r0,0x20
1372 1:      l.lbz   r5,5(r4)
1373         l.andi  r5,r5,0x20
1374         l.sfeq  r5,r6
1375         l.bnf   1b
1376          l.nop
1377
1378         /* Write character */
1379         l.sb    0(r4),r7
1380
1381         /* Check UART LSR THRE|TEMT (hold, empty) bits */
1382         l.addi  r6,r0,0x60
1383 1:      l.lbz   r5,5(r4)
1384         l.andi  r5,r5,0x60
1385         l.sfeq  r5,r6
1386         l.bnf   1b
1387          l.nop
1388 #endif
1389         EMERGENCY_PRINT_LOAD_GPR6
1390         EMERGENCY_PRINT_LOAD_GPR5
1391         EMERGENCY_PRINT_LOAD_GPR4
1392         l.jr    r9
1393          l.nop
1394
1395 /*
1396  * DSCR: prints a string referenced by r3.
1397  *
1398  * PRMS: r3             - address of the first character of null
1399  *                      terminated string to be printed
1400  *
1401  * PREQ: UART at UART_BASE_ADD has to be initialized
1402  *
1403  * POST: caller should be aware that r3, r9 are changed
1404  */
1405 ENTRY(_emergency_print)
1406         EMERGENCY_PRINT_STORE_GPR7
1407         EMERGENCY_PRINT_STORE_GPR9
1408
1409         /* Load character to r7, check for null terminator */
1410 2:      l.lbz   r7,0(r3)
1411         l.sfeqi r7,0x0
1412         l.bf    9f
1413          l.nop
1414
1415         l.jal   _emergency_putc
1416          l.nop
1417
1418         /* next character */
1419         l.j     2b
1420          l.addi r3,r3,0x1
1421
1422 9:
1423         EMERGENCY_PRINT_LOAD_GPR9
1424         EMERGENCY_PRINT_LOAD_GPR7
1425         l.jr    r9
1426          l.nop
1427
1428 /*
1429  * DSCR: prints a number in r3 in hex.
1430  *
1431  * PRMS: r3             - a 32-bit unsigned integer
1432  *
1433  * PREQ: UART at UART_BASE_ADD has to be initialized
1434  *
1435  * POST: caller should be aware that r3, r9 are changed
1436  */
1437 ENTRY(_emergency_print_nr)
1438         EMERGENCY_PRINT_STORE_GPR7
1439         EMERGENCY_PRINT_STORE_GPR8
1440         EMERGENCY_PRINT_STORE_GPR9
1441
1442         l.addi  r8,r0,32                // shift register
1443
1444 1:      /* remove leading zeros */
1445         l.addi  r8,r8,-0x4
1446         l.srl   r7,r3,r8
1447         l.andi  r7,r7,0xf
1448
1449         /* don't skip the last zero if number == 0x0 */
1450         l.sfeqi r8,0x4
1451         l.bf    2f
1452          l.nop
1453
1454         l.sfeq  r7,r0
1455         l.bf    1b
1456          l.nop
1457
1458 2:
1459         l.srl   r7,r3,r8
1460
1461         l.andi  r7,r7,0xf
1462         l.sflts r8,r0
1463          l.bf   9f
1464
1465         /* Numbers greater than 9 translate to a-f */
1466         l.sfgtui r7,0x9
1467         l.bnf   8f
1468          l.nop
1469         l.addi  r7,r7,0x27
1470
1471         /* Convert to ascii and output character */
1472 8:      l.jal   _emergency_putc
1473          l.addi r7,r7,0x30
1474
1475         /* next character */
1476         l.j     2b
1477         l.addi  r8,r8,-0x4
1478
1479 9:
1480         EMERGENCY_PRINT_LOAD_GPR9
1481         EMERGENCY_PRINT_LOAD_GPR8
1482         EMERGENCY_PRINT_LOAD_GPR7
1483         l.jr    r9
1484          l.nop
1485
1486 /*
1487  * This should be used for debugging only.
1488  * It messes up the Linux early serial output
1489  * somehow, so use it sparingly and essentially
1490  * only if you need to debug something that goes wrong
1491  * before Linux gets the early serial going.
1492  *
1493  * Furthermore, you'll have to make sure you set the
1494  * UART_DEVISOR correctly according to the system
1495  * clock rate.
1496  *
1497  *
1498  */
1499
1500
1501
1502 #define SYS_CLK            20000000
1503 //#define SYS_CLK            1843200
1504 #define OR32_CONSOLE_BAUD  115200
1505 #define UART_DIVISOR       SYS_CLK/(16*OR32_CONSOLE_BAUD)
1506
1507 ENTRY(_early_uart_init)
1508         l.movhi r3,hi(UART_BASE_ADD)
1509         l.ori   r3,r3,lo(UART_BASE_ADD)
1510
1511 #if defined(CONFIG_SERIAL_8250)
1512         l.addi  r4,r0,0x7
1513         l.sb    0x2(r3),r4
1514
1515         l.addi  r4,r0,0x0
1516         l.sb    0x1(r3),r4
1517
1518         l.addi  r4,r0,0x3
1519         l.sb    0x3(r3),r4
1520
1521         l.lbz   r5,3(r3)
1522         l.ori   r4,r5,0x80
1523         l.sb    0x3(r3),r4
1524         l.addi  r4,r0,((UART_DIVISOR>>8) & 0x000000ff)
1525         l.sb    UART_DLM(r3),r4
1526         l.addi  r4,r0,((UART_DIVISOR) & 0x000000ff)
1527         l.sb    UART_DLL(r3),r4
1528         l.sb    0x3(r3),r5
1529 #endif
1530
1531         l.jr    r9
1532          l.nop
1533
1534         .align  0x1000
1535         .global _secondary_evbar
1536 _secondary_evbar:
1537
1538         .space 0x800
1539         /* Just disable interrupts and Return */
1540         l.ori   r3,r0,SPR_SR_SM
1541         l.mtspr r0,r3,SPR_ESR_BASE
1542         l.rfe
1543
1544
1545         .section .rodata
1546 _string_unhandled_exception:
1547         .string "\r\nRunarunaround: Unhandled exception 0x\0"
1548
1549 _string_epc_prefix:
1550         .string ": EPC=0x\0"
1551
1552 _string_nl:
1553         .string "\r\n\0"
1554
1555
1556 /* ========================================[ page aligned structures ]=== */
1557
1558 /*
1559  * .data section should be page aligned
1560  *      (look into arch/openrisc/kernel/vmlinux.lds.S)
1561  */
1562         .section .data,"aw"
1563         .align  8192
1564         .global  empty_zero_page
1565 empty_zero_page:
1566         .space  8192
1567
1568         .global  swapper_pg_dir
1569 swapper_pg_dir:
1570         .space  8192
1571
1572         .global _unhandled_stack
1573 _unhandled_stack:
1574         .space  8192
1575 _unhandled_stack_top:
1576
1577 /* ============================================================[ EOF ]=== */